Garbage Disposal Humming But Not Working — How to Fix It

You flip the switch and hear that familiar hum — but nothing’s grinding. The motor’s trying, but the blades aren’t spinning. This is one of the most common garbage disposal problems, and in most cases, you can fix it yourself in under 15 minutes without calling anyone.

What’s Happening Inside

When a disposal hums but won’t spin, the motor is getting power but something is preventing the grinding plate from turning. Usually it’s one of two things:

Something’s jammed — a bone, pit, piece of glass, or utensil got wedged between the impeller plate and the grinding ring
Motor overheated — the disposal worked too hard and tripped its internal breaker

The humming is the motor straining against whatever’s stopping it. If you let it hum too long, it can burn out the motor — so don’t just leave it running hoping it’ll fix itself.

Safety First

Before you stick your hand anywhere near a garbage disposal:

⚠️ ALWAYS turn off the power. Flip the switch to OFF and unplug the unit under the sink. If it’s hardwired, turn off the breaker. Disposals can turn on unexpectedly if the switch is faulty.

⚠️ NEVER put your hand inside the disposal. Even with power off, the blades are sharp and something might be spring-loaded.

⚠️ Use tools, not fingers. Tongs, pliers, or the Allen wrench — not your hand.

Quick Fix: The Reset Button

Start here. Every disposal has a thermal overload button, usually a small red or black button on the bottom of the unit.

Turn off the disposal switch
Wait 5 minutes for the motor to cool
Find the reset button on the bottom of the unit (look under the sink)
Press it in firmly — you should feel it click
Turn the switch back on

Did it work? Great, you’re done. The motor just overheated from grinding too hard.

Still humming? There’s a jam. Move to the next step.

The Allen Wrench Method (Recommended)

Most disposals have a hex socket on the bottom that lets you manually rotate the grinding plate. This is the safest and most effective way to clear a jam.

You’ll need: 1/4 inch Allen wrench (hex key). Many disposals come with one — check under your sink or in your junk drawer.

Turn off and unplug the disposal (or flip the breaker)
Find the hex socket — it’s in the center of the bottom of the disposal
Insert the Allen wrench and turn back and forth
Work it until it moves freely — you’re breaking whatever’s jamming the plate loose
Remove the wrench
Use tongs or pliers to reach in from above and remove whatever was jamming it (DO NOT use your hand)
Press the reset button
Restore power and test

Time: 5-10 minutes. Cost: Free.

If you don’t have an Allen wrench, you can use a wooden broom handle from above to try to rotate the blades — but the wrench method is much more effective.

What If There’s No Jam?

If the disposal turns freely with the Allen wrench but still just hums when you turn it on:

Check the reset button again — really press it firmly
Listen for the hum — is it a strong hum or weak? Weak hum might mean a failing motor or capacitor
Check power — is the outlet working? Test with another device
Look at the age — disposals last 8-12 years. If it’s old, the motor might be failing

If the plate spins freely by hand but won’t spin with power, you likely have a motor issue. At that point, replacement is usually more cost-effective than repair.

Common Jam Culprits

These things frequently jam disposals:

Fruit pits (peach, avocado, cherry)
Bones (chicken bones especially)
Broken glass (remove very carefully)
Utensils (spoons fall in more than you’d think)
Fibrous foods (celery, corn husks, artichokes — these wrap around the blades)
Grease buildup (hardens and gums up the works)

What NOT to Put in a Disposal

While we’re here — prevent future jams by avoiding:

Grease and oil (solidifies and clogs)
Fibrous vegetables (celery, asparagus, corn husks)
Starchy foods (pasta, rice — they expand and paste up)
Coffee grounds (they accumulate and compact)
Eggshells (membrane wraps around blades)
Bones (small ones are okay, big ones aren’t)
Non-food items (obviously)

Can You Fix It Yourself?

✅ DIY-Friendly If:

The motor hums (proving it has power)
You have an Allen wrench or can get one
You’re comfortable reaching under the sink
The disposal is less than 10 years old

🛑 Call a Pro (or Replace) If:

No hum at all (electrical issue)
Reset doesn’t work and there’s no jam
The disposal is very old (12+ years)
You smell burning or see smoke
The unit is leaking

Step-by-Step Summary

Turn off power — switch off, unplug, or breaker
Press the reset button — bottom of unit, let it click
Test — if it works, you’re done
Still humming? Get the Allen wrench — 1/4 inch, bottom socket
Rotate manually — back and forth until free
Remove the obstruction — tongs or pliers, never hands
Reset and test

What If It Needs Replacing?

Disposals cost $80-300 for the unit, plus $100-200 for installation if you don’t DIY. Signs it’s time for a new one:

Frequent jams despite proper use
Motor burns out (hums weakly or not at all)
Persistent leaks from the unit itself
Age 10+ years with problems

If you’re replacing, consider:

1/3 HP: Budget, light use only
1/2 HP: Standard, handles most households
3/4 HP+: Heavy use, fewer jams, quieter operation

Prevent Future Jams

Run cold water before, during, and after grinding (15-30 seconds after)
Feed slowly — don’t shove everything in at once
Avoid problem foods — see the list above
Clean monthly — grind ice cubes with rock salt, or use disposal cleaning pods
Run it regularly — even if you don’t have much to grind, run it weekly to prevent rust and buildup

The Bottom Line

A humming disposal is almost always a jam or a tripped reset button. The fix takes 10 minutes and costs nothing if you have an Allen wrench. If the motor is truly dead, replacement is straightforward — but try the simple fixes first.

Don’t let the disposal just sit there humming. Every minute it hums without spinning is stress on the motor. Turn it off, fix the jam, and get back to scraping plates without a second thought.